Leak Test Air

SOFC STACK NITROGEN LEAK TESTING BY MASS FLOW MEASUREMENT

Leak testing is an essential operation in the SOFC stack production process, since it verifies that no leakage is associated to the electrochemical system, either internal to the system itself or towards the outside, simulating real operating condition.

After the complete assembly of the SOFC stack, a crucial step is to verify the tightness of its main circuits (hydrogen circuit and oxygen circuit), both towards each other and towards the external environment. In fact, even if the single components (MEAs, bipolar plates, gaskets…) have been already tested during their production processes, the overall assembly could bring additional sources of leakages. Avoiding them is crucial to assess the safety and the efficiency of the system once operating.

Accordingly, the tightness of the SOFC stack is of paramount importance to ensure the efficiency and the long term reliability of the fuel cell system, such as its safety: a leakage of hydrogen at the very high operating temperature (around 800 °C) would immediately turn into self-ignition.

DESCRIPTION
BENEFITS
TECH SPECS
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DESCRIPTION

Single station N₂ leak test for SOFC Stacks, with manual or automatic loading/unloading. Different sizes and models of stacks can be tested, by means of related fixtures for their connections.

Principle of measurement: nitrogen mass flow measurement, by way of Tecna measuring devices.

The bench provides a single station, assembled on a welded painted steel frame with cover panels and automatic door. The cabinet containing the electric switchboard is on the left-hand side of the bench, while the process components, including the measuring devices, are located on the right-hand side. The access to the stations is protected by safety light curtains. Only electrical supply, air and nitrogen supply are needed to run the machine.

The measuring device – with possibility to have a touch screen display at sight, so that it is possible to look into the values of pressure/flow rate of the test phase – is installed in the bench.

The fixture is automatically actuated and allows the coupling between the bench and the stack under test.

The bench incorporates an industrial PC which performs HMI functions while supervision of the process is made by a PLC. The software is configurable so that it is possible to:

Set machine parameters
Create different recipes, according to required test parameters
Manage the automatic cycle as well as the manual cycle
Set counters and production data
Manage levels of access

BENEFITS

Dedicated electric cabinet
Easy access to process circuit by way of front doors
Configurable HMI touch screen interface
Push button panel and light signals for easiness of the operator
High accuracy of the system
Manual Datamatrix reader
The equipment can be interfaced with a Manufacturing Execution System (MES) to receive the recipe to use (or the reference of the recipe to use) and save the data obtained.

TECH SPECS

Test medium: Nitrogen
Test method: flow measurement
Pressure range for test: 300 – 900 mbar rel
Description of the test: H₂ and O₂ chambers are tested separately and while the test is performed in one chamber the other is kept at a specific pressure. Leak detection from one chamber towards the other and extern (no discrimination cycle is planned)
Leakage flow rate range: 3 – 30 sccm

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